Liu L, Harding J E, Evans P C, Gluckman P D
Research Center for Developmental Medicine and Biology, University of Auckland, New Zealand.
Endocrinology. 1994 Sep;135(3):895-900. doi: 10.1210/endo.135.3.8070384.
Insulin-like growth factor-I (IGF-I) in the maternal circulation may have a role in the regulation of placental function and fetal growth, but its mechanisms of action are not known. We studied the effects of maternal IGF-I infusion (30 micrograms/kg.h for 4 h) in eight chronically catheterized pregnant sheep. IGF-I infusion caused an increase in fetal blood glucose concentrations, but no change in placental or fetal glucose uptake. Maternal plasma insulin concentrations fell. Placental lactate production increased by 56%, with most of this lactate taken up by the fetus. Maternal and fetal blood amino nitrogen concentrations fell, but fetal protein oxidation was unchanged. IGF-I infusion did not change feto-placental oxygenation, placental blood flow, or placental transfer by simple or facilitated diffusion. The metabolic effects of maternal IGF-I infusion in part oppose those of fetal IGF-I. We hypothesize that the balance of maternal and fetal IGF-I concentrations contributes to the regulation of substrate distribution between mother, placenta and fetus, and may thus mediate the nutritional regulation of fetal growth.
母体循环中的胰岛素样生长因子-I（IGF-I）可能在胎盘功能和胎儿生长的调节中发挥作用，但其作用机制尚不清楚。我们研究了对八只长期插管的怀孕绵羊进行母体IGF-I输注（30微克/千克·小时，持续4小时）的效果。IGF-I输注导致胎儿血糖浓度升高，但胎盘或胎儿的葡萄糖摄取没有变化。母体血浆胰岛素浓度下降。胎盘乳酸生成增加了56%，其中大部分乳酸被胎儿摄取。母体和胎儿血液中的氨基氮浓度下降，但胎儿蛋白质氧化没有变化。IGF-I输注并未改变胎儿-胎盘的氧合、胎盘血流量或通过简单或易化扩散的胎盘转运。母体IGF-I输注的代谢作用部分与胎儿IGF-I的作用相反。我们推测，母体和胎儿IGF-I浓度的平衡有助于调节母体、胎盘和胎儿之间底物的分配，从而可能介导胎儿生长的营养调节。
